#7 of 10: Top Reasons for Poor Premium IOL Outcomes and How to Remedy Them: Managing IOL CalculationsA 10 year study conducted by OMIC revealed that IOL power calculations represent the single largest malpractice risk to a practicing ophthalmologist.¹ In the most recent series on managing the ocular surface, the PHACO study² was revisited in that poor data acquisition in terms of keratometry, corneal topography, and/or biometry often leads to IOL power calculation errors of up to 1-2 diopters.
Assuming the patient has a pristine and/or stable ocular surface, the emphasis should then be on the actual biometry device utilized and IOL calculation software chosen. To make matters even more complicated, if the patient has had previous refractive surgery and IOL, calculation decisions become more challenging.
With rising patient expectations, especially in the premium IOL world, IOL calculations need to be exact or the added costs of piggybacking IOLs, laser vision correction, and/or limbal relaxing incisions as enhancement options will become more apparent.
There are general principles in IOL calculation that must be avoided: if axial length is measured too short, the patient will have a myopic surprise and, if measured too long, a hyperopic surprise. In a normal 24 mm or so eye, for every 1 mm error in axial length (AL) measurement, there is typically a 2.5-3.0 diopter error in IOL power. In shorter eyes, less than 22 mm, there can be up to a 7.5 diopter error in IOL power for every mm error in AL measured.³ Keratometry error of 1 diopter in curvature readings can mean an additional error of 1 diopter in IOL power.
To carry out successful cataract surgery with the proper IOL power, four variables are critical to obtaining the premium outcome: axial length, keratometry, effective lens position (ELP), and desired postoperative refraction. The ELP is the effective position of the IOL (the principal plane of the thin lens) relative to the anterior corneal vertex, which is different from the old term, anterior chamber depth (ACD), which ignores central corneal thickness.
Other variables such as lens thickness (LT) and horizontal white to white corneal diameter measurement (HWTW) are additional variables in newer generation IOL formulas, such as Holladay II, to better predict ELP and master the intended targeted refraction postop. Devices such as the newest IOLMaster 500 (Carl Zeiss) finally implement Holladay II software, especially helpful for short and long eyes.
The challenge with longer eyes are myopic staphyloma, and devices that utilize optical coherence tomography (OCT), such as the IOLMaster 500 or LenStar, will more accurately measure axial length than ultrasound in these difficult situations. Overall, accurate measurements of keratometry, axial length, ACD, HWTW, LT are critical to obtaining the correct IOL power.
In post refractive surgery situations, the challenges and expectations from patients are even greater. Conventional keratometry and topography measurements of the cornea in these patients are inaccurate: in myopic LASIK/PRK, the anterior corneal curvature is flatter than the posterior curvature, often resulting in an IOL power underestimation, or hyperopic surprise postoperatively.
In hyperopic LASIK/PRK, the reverse is true due to the anterior corneal curvature being steeper than its posterior curvature. In RK patients, both the anterior and posterior corneal curvatures are flatter due to the peripheral weakening in the cornea, and typically a hyperopic surprise occurs in these patients as well.
There are several methods available for IOL power determination in post refractive surgery patients. The clinical history method (CHM) basically subtracts the patient’s surgically induced refractive change from the pre-refractive surgery keratometry reading to determine current corneal power utilizing the general formula [K = Pre-RS K + (Pre-RS SE – Post-RS SE)]. The drawbacks with this formula are the need to obtain preop refractive surgery data if still available and the potential inaccuracy of the postop refraction due to a myopic shift from the cataract.
The contact lens method (CLM) utilizes a rigid gas permeable contact lens to perform an over-refraction using the general formula [K=BC + D + (ORcl – MRSEnocl)]. The major drawback of this method is it does not compensate for the change in the back-to-front surface ratio and it requires additional chair time. Both of these methods are available at the ascrs.org website for inputting information as well as in the IOLMaster 500 software template for post refractive surgery.
The Masket regression method⁴ utilizes the formula K= LSE x (-0.326) + 0.101 where LSE is the excimer laser spherical equivalent treatment applied. With this formula there is approximately 1 diopter adjustment for every 3 diopters of excimer laser treatment applied. The formula I use consistently now without any additional chair time or need to obtain past data is the Haigis-L formula as part of the IOLMaster 500 program. The Haigis-L formula avoids using corneal power readings to determine the effective ELP.
On the IOLMaster 500, the only criterion the surgeon must select is whether or not the patient had previous myopic or hyperopic laser vision correction. The only drawback with the Haigis-L formula is it cannot be used for previous RK patients. For RK patients, I still use the ascrs.org website and utilize my APP corneal power reading from my OPDIII (Marco Ophthalmics) and look at angle kappa and spherical aberration data from the same system to help me select the correct IOL power and premium IOL type for these patients.
One last evolving technology especially helpful in post-refractive surgery cataracts is intraoperative aberrometry (Wavetec ORA) to measure for correct IOL power on the OR table itself. On average, it only takes an additional 2-3 minutes of operating time to ensure the precise IOL power.
In the end, managing IOL calculations is critical in obtaining the premium result in a premium patient. With patient expectations ever-growing, especially in the post refractive surgery subpopulation of cataract patients, IOL power and hitting the correct targeted refraction is mandatory.
Stay tuned for my next remedy on how to handle the unsatisfied patient who has undergone a premium IOL surgery.
¹10 year OMIC study. Survey of Ophthalmology 43:356-360, 1999.
²Trattler W, Goldberg D, Reilly C. Incidence of concomitant cataract and dry eye prospective health assessment of cataract patients. Presented at World Cornea Congress April 8, 2010 Boston, MA. ³Quality of Vision: Essential Optics for the Cataract and Refractive Surgeon. Holladay J. Slack Incorporated, 2007. ⁴J Cataract Refract Surg. Masket S et al. 2006; 32:430-434.
Heavenly Sight: A Vision Out of Blindness
Throughout African American history there has been a plethora of talented and influential blind musicians. Author Lee Breuer states that “There is a general total world historical connection between blindness and mystical insight… The clearest representation of that of course in the United States is the black gospel singer.”
A 2004 study from the University of Montreal confirmed the existence of this “mystical insight,” as the study concluded that those who lose their sight at early ages can detect differences in tonal pitch better than the sighted, often leading to musical ability.
In honor of Black History Month, Murray Street Productions, a New York-based marketing and production firm, has produced a series of radio specials paying tribute to the rich history of blind musicians in the African American community.
Its research has generated a variety of original interviews and transcripts, while unearthing rare archival and commercial recordings. It has brought to life the stories of several influential blind musicians and shed insight onto their impact in the music industry.
The radio series has been playing on Public Radio International stations this month, and Murray Street Productions is now asking the public to help preserve its research in a complete audio documentary and multimedia website.
The company’s blind-friendly website, Heavenlysight.org, will bring the library of interviews, musical recordings, multimedia content, and blog posts to the public as a resource for education and entertainment. In order to obtain the funding needed to make Heavenlysight.org possible, Murray Street Productions launched a Kickstarter campaign, hoping to raise $18,000 for the design and development of the site. If you want to pitch in and help, visit Heavenly Sight’s Kickstarter page here.
The Visual MD Brings Health & Wellness Education to the Masses
The most recent video to be released from TEDMED 2011 is a presentation from Alexander Tsiaris on his revolutionary health information website, The Visual MD.
Tsiaris is a world-renowned technologist, journalist, photographer, painter, author, and entrepreneur who made his way into the world of medical imaging by photographing a story about ophthalmic techniques.
From there, he taught himself the physics and mathematics required to create his own lenses used for microscopic and endoscopic imaging. Tsiaris later learned how to write his own computer programs, and, using his knowledge of physics and light, created visualization software for human anatomy. This led him to start his own medical imaging company, Anatomical Travelogue.
While Tsiaris’ medical images have widely been used by doctors and scientists, his newest venture, The Visual MD, brings them to the public to improve patient education.
While most doctors do their best to explain tests and procedures to their patients, more often than not, patients do not fully understand what their tests results mean, why they are taking the tests, and how certain procedures work. Similarly, when people attempt to improve their health with diet and exercise, most do not truly understand how their diet affects them or how certain exercises affect their body.
The Visual MD hopes to change that by giving the public the tools and education to “visually understand and manage their health.”
The website features a huge database of educational videos, interactive models, explanations of results for dozens of tests, and the largest nutritional library ever created.
Tsiaris explains how it all works in his TED Talk:
For those of you who had the pleasure *cough* of viewing our Twit Pics over the past few weeks, you have probably noticed the theme: Gross pictures of eyes. For your viewing pleasure, we will now proudly archive these repulsive gems on the Freaky Friday page. Take a quick peak and see if you could handle being an ophthalmologist!
Please feel free to submit, and stop by every Friday to get your freaky fix!
Dr. Karpecki’s Dream Dry Eye Clinic
What instruments and tests are best for building a dry eye subspecialty clinic?
If I could build my ‘dream’ dry eye clinic, these are some the instruments I’d want to have: 
The TearLab Osmolarity Device: It’s a test that takes about 5-10 seconds to measure the osmolarity of a patient’s tears. It has an almost 90% positive predictive value, which is three times more accurate than any other test including tear break-up or Schirmer’s. It also can tell you if the topical medications you’ve chosen for the patient are working based on an improvement in osmolarity after a month’s treatment. And having received a CLIA waiver this past month allows a reimbursement of over $46 each time it is appropriately used. No other test is as accurate or reimburses for performing a dry eye 
measurement.
The iCare Tonometer: Consider a tonometer that doesn’t require drops such as fluress or anesthetic, which can affect the ocular surface and tearfilm. The iCare tonometer is also impressive in that there is no puff of air so patient response is positive. It also has been shown to be accurate and is portable, making it easy to use anywhere for your dry eye patients and in any lane.
TelScreen EyeRes: I don’t know of a better or more efficient way to educate patients than showing them an image or video of their own eyes. The high resolution of this system makes capturing any image in the lane possible and it greatly increases compliance as patients know I’ll take another image at their next visit to gauge improvement.
Fluramene Dye: Nothing is more efficient than one bottle that has found a way to combine fluoresceine and lissamine green dye. It seems to be more sensitive than each alone and it is certainly far more efficient. Two minor things to be aware of however: it can burn certain dry eye patients and the bottle tip is a little large so practice at instilling a small drop is essential.
Eyemaginations LUMA: If there is a better patient education tool out there, I don’t know what it could be. LUMA allows the doctor to explain the dry eye condition or any disease to a patient via images. I can show the animations, draw on, talk about treatment and even display the patient point of view. In 30-60 seconds I can educate a patient about dry eye and punctal plugs, for example, that used to take 3-5 minutes or more.
Topography: Topography used to cost $65,000 when first introduced and now you can obtain a topographer that does five times as much as the original and costs under six figures (e.g. the Topcon CA-200). Topography can reveal dry eye via the patterns that are observed. There are even topographers that measure tear film break-up time and the tear meniscus height (Oculus Keratograph).
Opt-align: This new system measures ocular alignment in about 30-60 seconds providing information such as phorias, vertical imbalances, proprioceptive disparity and the reasons for asthenopia symptoms that often mimic dry eye symptoms. It has saved me hours and more importantly helped diagnose “dry eye” patients that really had significant ocular alignment issues; and, when treated with the prism the machine recommended, their symptoms were completely eliminated.
Specular Microscopy: There are numerous times when patients have had symptoms of contact lens intolerance that were thought to be dry eye, for example, that turned out to be endothelial issues ranging from decompensation to simple stress on the endothelial cells indicated by pleomorphism and polymegathism. The Konan CellChek is a great machine that captures signs of early endothelial stress and readily displays below average numbers.
OM Solutions: After having all of these in place you then need a system or staff to help you manage the medical practice component including credentialing, proper coding, billing, accounts receivable, insurance verification, tracking, proper protocol, driven testing, etc. You can outsource these activities to various companies: the most effective of which, in my experience, is OM Solutions. With those headaches out of the way, it’s a lot easier to put the medical clinical component into optometric practice.
With so much new technology in the healthcare field like EMR systems, “quantified-self” gadgets, and online tools, it’s easy to get caught up in the fanfare without taking the time to truly examine the benefits and hindrances of each product.
Daniel Palestrant, MD and Adam Sharp, MD, co-founders of the popular online physician community Sermo, believe that many new EMR systems diminish the patient-doctor experience, lowering the overall quality of our healthcare system.
The first step toward improving the broken system, they claim, is “Referrals, Reinvented.” This idea is what led the two physician/entrepreneurs to leave Sermo and pursue a new venture, Par8o.
The company’s product is yet to be released, but Par8o’s blog serves as a passionate manifesto, harshly criticizing the commoditization of physicians as well as healthcare software that prioritizes “profit and politics” over patient care.
The company’s name comes from the Italian economist Vilfred Pareto, who preached that “efficiency comes from effectively matching supply and demand.” Palestrant explains, “For this efficiency to occur, there needs to be as few intermediaries as possible between the reciprocal parties and a clear, transparent understanding of the goods or services being provided.”
To foster better efficiency within the healthcare community, Par8o’s founders are using their software and social networking experience to improve the physician referral process. Often times when a general practitioner sees a health problem in a patient, they call in a specialist that can better treat or diagnose the problem. In an article from Xconomy, Palestrant explains that of all the millions of referrals made every year, somewhere between 20-40 percent never actually result in another appointment.
Par8o will provide software that enables doctors to make referrals more efficiently and effectively.
“Not only can we make sure that the referral occurs, but doctors in all parties involved can track and manage that process,” he continued. “They can make sure the appointment actually occurred. We’re then able to allow the healthcare system to start introducing the Pareto efficiencies. In this case the specific challenge is what healthcare provider is best suited to address this [patient's problem].”
The founders are keeping quiet regarding the specifics of their business model and how the product will function, as they are busy testing and tweaking their software.
This hush-hush attitude lends itself to some creative marketing, as Par8o’s website gives no details as to what the product actually is. Instead, visitors will find a series of passionate and insightful blog posts outlining what the company hopes to achieve as well as a section called “Pareto Sightings,” which features a series of playful photos of a Vilfred Pareto cutout wearing a lab coat at various landmarks in Boston, near Par8o’s offices in Cambridge. All of this gives the brand a sort of mystique that is sure to create some buzz within the medical community.
Par8o will likely launch sometime within the next few months. If you want to be among the first to hear about it, you can sign up for the company’s product launch notification here.
A recent Fast Company article by Adam Bluestein has colorfully reinforced one of Noble Vision Group’s core convictions: Mobile Technology is Changing the Face of Healthcare.
As healthcare costs continue to rise, tablet and smartphone apps are steadily entering the mainstream as appealing and less expensive alternatives to non-invasive procedures and tests. People can now test their vision, count calories, send microscopic images, and more, all using mobile devices.
Fast Company illuminated the article with the following graphic, which illustrates the what and how of emerging mobile health apps. For a deeper look into each one, follow the links we’ve dropped in below.
The CCHIR: Researching Web 2.0 & Mobile Technology in HealthcareWith Web 2.0 and mobile technology making their way to the forefront of pharmacology and public health, there has been a growing need for in-depth research into their effects and benefits.
Many pharma companies and healthcare systems are connecting with consumers through mobile apps, social media, and other online platforms, but what do these new systems actually do to improve health literacy and patient education?
It’s questions like this that prompted Fort Lauderdale’s Nova Southeastern University College of Pharmacy to open America’s first Center for Consumer Health Informatics Research (CCHIR).
The Center’s mission is to “generate discoveries that leverage the potential of consumer health informatics to improve patient health.” They define health informatics as “the field that studies and incorporates patient preferences, behaviors, tools, and technologies in order to help inform their decision making and manage their health.”
The Center conducts research in six main categories—mobile health (mHealth), social media in healthcare, online health information seeking, eHealth/health literacy, public health informatics, and pharmacovigilance.
The CCHIR is currently conducting studies investigating the use of text messaging to improve medication adherence in diabetes and HIV patients. Others studies include inquiries into pharmacists’ use of blogs and social networks, the safety of online health information, the readability of online drug information, the technology used in public health efforts, identifying prescription drug abuse through social media, and more.
As Web 2.0 technology advances, research from institutes like the CCHIR will be extremely valuable for patients, doctors, and pharma companies. Keep an eye out for some interesting studies coming from the Center in the near future.
Until then, we thought we’d share this infographic with you, illustrating the CCHIR’s findings on pharmacist-generated Twitter content.
Daniel Kraft: TEDMED 2011
In this inspirational presentation from TEDMED 2011, Daniel Kraft, a Stanford and Harvard-trained physician-scientist, offers up some ideas regarding how the medical industry can move from the present to the future.
If you saw the last TED Talk we posted from Daniel Kraft, he explains the plethora of emerging medical technologies that have the power to change medicine as we know it.
Today, 25 percent of all US physicians own a tablet device, while average consumers can use mobile devices as diagnostic tools and share healthcare information via social networking. Mobile devices also provide consumers with the concept of “quantified self,” helping them monitor and improve their health.
Kraft explains that in order to incorporate all this new technology into healthcare systems, we need to redefine how the system is structured. “If we want to get from San Diego to New York, on your car you may not want to strap on new wings and a rocket motor—you may actually want to build a jet fighter to get there in a couple hours.”
#6 of 10: Top Reasons for Poor Premium IOL Outcomes and How to Remedy Them: Managing the Ocular Surface
Managing patient expectations, the preoperative evaluation, corneal astigmatism, posterior capsular opacification, and addressing cystoid macular edema are all critical in making the premium patient happy with a premium outcome. However, ignoring the ocular surface, one of the remaining reasons for poor premium IOL outcomes, will lead to a dissatisfied patient from a preoperative, intraoperative, and/or postoperative perspective.
Dry eye syndrome (DES), blepharitis/meiboimian gland dysfunction (MGD), allergy, and epithelial basement membrane disease (EBMD) are the most common causes for poor ocular surface function in the premium IOL patient. Approaching the ocular surface from a tear layer approach will help manage and prevent many of the problems associated with such a problem.
Recently, the International Delphi Panel/DEWS redefined dry eye as being a multifactorial disease of the ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface.¹ Furthermore, dry eye is accompanied by an increase in tear film osmolarity and inflammation of the ocular surface. Dry eye affects approximately 20.7 million people in the United States² and is most commonly observed in older women over the age of 50.³
Other common causes of dry eye are the American “fast food” diet high in bad omega-6 and low in good omega-3 fatty acids, LASIK/other corneal refractive surgery procedures, diabetes mellitus, vitamin A deficiency, hepatitis C infection, low blink rate (Parkinson’s disease, computer vision syndrome, cosmetic blepharoplasty, contact lenses, and medications (diuretics, antihistamines, BCPs, tricyclic antidepressants, anticholinergics, antispasmodics, HRT).
The preoperative evaluation must include a global evaluation of the patient, because a poor ocular surface can affect the accuracy of preoperative critical measurements such as keratometry, corneal topography and axial biometry. The PHACO study (prospective health assessment of cataract patients’ ocular surface) led by William B. Trattler, MD, and colleagues confirmed that most patients who undergo cataract surgery are asymptomatic, but 62% have a tear breakup time of less than 5 seconds, 50% have central corneal staining, and 21% have abnormal Schirmer test scores of less than 5 mm. As much as 1 D to 2 D of error in IOL power calculations as a result of such poor data acquisition can definitely hinder the ideal outcome, especially in premium IOL patients.
My approach to the ocular surface is that of a tear layer etiology and management, which typically is overlapping, requiring multiple treatment modalities in order to achieve an improved ocular surface.
The lipid layer is most commonly affected by patients with acne rosacea or some ocular variant of such creating what we coin as blepharitis, meibomitis, MGD, or simply lid margin disease. Management of such includes warm compresses, lid massage, lid scrubs, topical azithromycin (Azasite Plus, ISV-502, Insite Vision) and/or tobramycin/dexamethasone/loteprednol (Tobradex ST. Alcon/Zylet, Bausch & Lomb), artificial tears that replace the oily layer (Systane Balance, Alcon/Retaine, Ocusoft), low dose doxycycline 50 mg/day, the Maskin meibomian gland probing/expressor technique (Rhein), and/or the potentially new curative Lipiflow thermal pulsation system (Tear Science).
The aqueous layer is typically affected by autoimmune disease such as lupus, rheumatoid arthritis, ulcerative colitis, diabetes, and thyroid disease. Management options include concomitant internist/rheumatologist/endocrinologist care, topical cyclosporine (Restasis, Allergan), punctual plugs, topical steroids such as loteprednol (Lotemax, Bausch & Lomb), and omega 3 fish oil nutrition. Tear film osmolarity is now easily detected with the Tear Lab device no more difficult than a tonopen IOP measurement. If osmolarity is elevated, I may customize my artificial tear regimen to include Blink tears (Abbott Medical Optics) as it has a beneficial effect on tear osmolarity. ⁵
The mucin layer insult is usually seen with vitamin A deficient, Stevens Johnson syndrome, graft versus host disease, and ocular cicatricial pemphigoid (OCP) conditions. Treating the underlying condition, topical cyclosporine due to its enhanced goblet cell density effect, and topical Freshkote (Focus Labs) are my treatments of choice in these circumstances. The latter also aids those with epithelial basement membrane dystrophy (EBMD) due to an enhanced oncotic pressure gradient effect at this level. Lastly, ocular allergy though fairly easy to treat will always aggravate dry eye and selecting a more specific H-1 receptor antihistamine/mast cell stabilizing pharmaceutical such as Lastacaft (Allergan) or Bepreve (Ista) will limit such side effects in the dry eye patient.
In the end, managing the ocular surface is crucial in not only obtaining accurate diagnostic data preoperatively but improving visual quality postoperatively by managing each patient based on a tear layer etiologic approach. Stay tuned for my next remedy for the premium IOL problem blog: managing IOL calculations with special attention to the post-refractive surgery patient.
¹Lemp M et al. Ocular Surface 2007; 5: 75-92. ²Market Scope. Report on the Global Dry Eye Market. St. Louis, Mo: Market Scope, July 2004. ³Schaumberg DA, Sullivan DA, Buring JE, Dana MR. Prevalence of dry eye syndrome among US women. Am J Ophthalmol. 2003; 136: 2318-2326.⁴Trattler W, Goldberg D, Reilly C. Incidence of concomitant cataract and dry eye prospective health assessment of cataract patients. Presented at World Cornea Congress April 8, 2010 Boston, MA.
